I'm all for the ideological sentiment behind this setup and approach. In many ways, this is 'the right way' when you're a small and close-knit team.
And that's the major caveat: this really only works at the very early stages.
In my experience (5 years at a startup that has gone from 30 to now 300 people) and with a heavy bent toward pragmatism, simply put, this doesn't scale.
If growth of the team is imperative for growth of the business (which in most cases, it is), then the shape of the team will change and the culture of the business will evolve away from openness and flexibility out of necessity.
You will get silos, whether you want them or not. If you know you want to scale, not prep'ing for that is akin to burying one's head in the proverbial sand.
Be transparent, but configure for partitioning.
Be flexible, but prepare to have some deadlines start to appear.
Keep prioritisation as simple as possible, but assume that it will get more complex and you will need people who can/want to manage that.
When you move from planning the next few sprints to strategising the next few years, you have to start anticipating problems before they arise across many fronts, not just the tech.
It doesn't mean spending an inordinate amount of time and money on getting that TechCrunch article, but when knowing your runway ends in 6 months, it would be extremely shortsighted not to be laying the groundwork for an investment round by everyone just going heads-down on product development.